Ultraviolet lamp housing

ABSTRACT

An ultraviolet lamp housing has side and end walls defining a relatively elongated lamp enclosure having an elongated opening at one side, in the operative position of the housing. An elongated ultraviolet lamp is mounted between the end walls. A pair of elliptical reflector sections are mounted in the enclosure for rotation about axes extending in spaced parallel relation to the lamp. The reflector sections have a first closed position in which they form an elliptical reflector having a first focus at the lamp and a second focus at the plane of the opening, and have a second closed position in which they are interposed between the lamp and the opening. The side of the lamp enclosure opposite to the opening is formed with a coolant duct and a heat sink is mounted in this duct and displaceable coordinate with the reflector sections. In the first closed position of the reflector sections, the heat sink is disposed in spaced relation to the closed reflector sections and toward the outer side of the coolant duct. In the second closed position of the reflector sections, the heat sink is moved inwardly to form an inner wall of the coolant duct. In another embodiment of the invention, the heat sink may be stationary and form the inner wall of the duct and, in this case, conduits for the flow of liquid coolant are superposed on the heat sink for extracting the heat of the lamp enclosure.

United States Patent 1191 Newman June 25, 1974 [75] Inventor:

1. ULTRAVIOLET LAMP HOUSING Henry C. Newman, Scotch Plains, NJ.

22' Filed: June 8, 1973 21 Appl. No.: 368,438

[52] U.S. Cl 240/4l.37, 240/44.1, 240/47, 240/103 B, 355/71, 355/101 [51] Int. Cl. F2lv 7/00 [58] Field of Search 240/41.37, 41.35 R, 44.1,v

240/51.ll R, 103 B, 47; 355/71, 30, 101; 350/289 Primary Examiner-Richard L. Moses Attorney, Agent, or Firm-Blum, Moscovitz, Friedman & Kaplan [5 7] ABSTRACT An ultraviolet lamp housing has side and end walls defining a relatively elongated lamp enclosure having an elongated opening at one side, in the operative position of the housing. An elongated ultraviolet lamp is mounted between the end walls. A pair of elliptical reflector sections are mounted in the enclosure for rotation about axes extending in spaced parallel relation to the lamp. The reflector sections have a first closed position in which they form an elliptical reflector having a first focus at the lamp and a second focus at the plane of the opening, and have a second closed position in which they are interposed between the lamp and the opening. The side of the lamp enclosure opposite to the opening is formed with a coolant duct and a heat sink is mounted in this duct and displaceable coordinate with the reflector sections. In the first closed position of the reflector sections, the heat sink is disposed in spaced relation to the closed reflector sections and'toward the outer side of the coolant duct. In the second closed position of the reflector sections, the heat sink is moved inwardly to form an inner wall of the coolant duct. In another embodiment of the invention, the heat sink may be stationary and form the inner wall of the duct and, in this case, conduits for the flow of liquid coolant are superposed on the heat sink for extracting the heat of the lamp enclosure.

15 Claims, 16 Drawing Figures PATENTEU N 25 I974 SHEET 1 OF 5 ULTRAVIOLET LAMP HOUSING BACKGROUND OF THE INVENTION Ultraviolet lamps are used on all types of web printed presses where the printed material is fed under the lamp housing or between two lamp housings, and ultraviolet lamps are used on all types of sheet fed printing presses where the printed material will be conveyed under the lamp housing, as well as on other devices where material printed or coated with ultraviolet curable ink or coating is conveyed past the lamp housing. If any such material or a web is stopped under the lamp housing, it will be damaged or destroyed, or may create a fire hazard. Consequently, it is necessary, in the case of stoppage of a web or the like, to immediately protect the web from the heat of the lamp.

As space is an extremely valuable commodity in a printing press, a small compact size of an ultraviolet lamp housing is essential. Since the housings are mounted in a location where personnel may contact them while performing their normal functions, it is important to provide that the external surface of an ultraviolet lamp housing be kept cool to prevent burns or shock or other danger to the personnel. Furthermore, rapid and simple maintenance procedures are essential for any type of printing operation.

It has long been known to use mercury vapor lamps for chemical reactions, particularly in combination with reflectors. Also, it is known to use shutters to prevent ultraviolet radiation escaping from the reflector lamp combination. However, shutters take up valuable space and take time to open and close.

Generally the reflectors are elliptical reflectors so arranged, with respect to the ultraviolet lamp, that the lamp is at a first focus of the ellipse and the plane of web movement is at a second focus of the ellipse. With the fixed reflectors in use up to now, even when shutters are moved in between the reflector ellipse and the web. and even if the shutters form part of the ellipse, they do not prevent concentration of the ultraviolet energy at the second focus of the ellipse which is the plane of movement of the web. Until the shutters completely close, most of the intense radiation will still impinge on the web.

Additionally, by closing off the reflector and lamp utilizing shutters, a great amount of heat is enclosed and directed back on the lamp, which can overheat the quartz lamp vessel, even when the lamp is reduced in power. Mercury vapor lamps are extremely sensitive to air cooling and, if subjected to cold air flowing around them, they will lose power, particularly if they are operating at reduced power levels.

In view of the foregoing considerations and disadvantages of known ultraviolet lamp housings for use on web printing presses and the like, there is a need for an improved compact ultraviolet lamp housing in which the web is immediately protected when it is stationary beneath the lamp housing.

SUMMARY OF THE INVENTION In accordance with the invention, a small compact ultraviolet lamp housing is provided in which the elliptical reflector is divided into two reflector sections mounted in a lamp enclosure for the rotation about respective axes extending in spaced parallel relation to a lamp mounted in the housing. In the operative position,

the two reflector sections define an elliptical reflector whose first focus is at the lamp and whose second focus is at the plane of web movement. In an inoperative position, the two reflector sections form a shutter, by being rotated to an opposite position in which they are interposed between the lamp and the plane of web movement.

The lamp housing, at its side opposite the open side across which passes the web, is formed with an air duct which may be associated with induced or forced draft means, and a heat sink is disposed in this air duct. In one embodiment of the invention, the heat sink is vertically displaceable in accordance with movement of the reflector sections. Thus, when the reflector sections are moved to a position in which they form an elliptical reflector, the heat sink is positioned near the upper side of the cooling air duct and the heat of the lamp is then transferred to the cooling air through the reflector section. When the reflector sections are moved to the position in which they are interposed between the lamp and the plane of web movement, the heat sink is automatically moved down adjacent the lamp and to the inner side of the air duct, whereby the heat sink absorbs the heat from the lamp and transfers this heat to the cooling air in the duct.

In a second embodiment of the invention, the heat sink is disposed at the inner or lower side of the duct at all times and is not movable and, in this case, liquid coolant conduits are associated with the outer side of the heat sink to absorb heat transferred to the heat sink from the lamp and to transfer this heat to the coolant air flowing through the air duct.

An object of the invention is to provide an improved small compact ultraviolet lamp housing for a wide range of uses including all types of web printing presses.

Another object of the invention is to provide such a lamp housing including two reflector sections movable between a first position in which they form an elliptical reflector reflecting ultraviolet energy to the plane of web movement and a second position in which they are interposed between the plane of web movement and the lamp.

A further object of the invention is to provide such a lamp housing including two reflector sections in association with a novel heat sink arrangement and a coolant air duct.

Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification and drawings.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the invention, reference F is had to the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of a single lamp housing embodying the invention;

FIG. 2 is a vertical sectional view taken on the line 2-2 of FIG. 1;

FIG. 3 is a view, similar to FIG. 2, but illustrating upper and lower lamp housings embodying the invention as arranged in operative relation with a printing web;

FIG. 4 is an elevation view illustrating lamp housings embodying the invention as associated with a printing press;

FIG. 5 is a longitudinal and vertical sectional view of the lamp housing taken on the line 55 of FIG. 1;

FIG. 6 is a transverse sectional view taken on the line 6-6 of FIG. 5, and showing the two reflector sections in the closed reflector position;

FIG. 6a is a view similar to FIG. 6 but illustrating the reflector sections as swung into a shutter position in which they are interposed between the lamp and the web;

FIG. 7 is a transverse sectional view taken on the line 7-7 of FIG. 5 and illustrating the drive for the shutter sections when the latter occupy the position of FIG. 6;

FIG. 7a is a view similar to FIG. 7 but illustrating the drive for the shutter sections when the latter occupy the position of FIG. 60;

FIG. 8 is a sectional view taken on the line 8-8 of FIG. 6;

FIG. 9 is a sectional view taken on the line 9-9 of FIG. 6a;

FIG. 10 is a horizontal sectional view taken on the line 10-10 of FIG. 5 and illustrating an adjustable heat shield;

FIG. 11 is an exploded partial perspective view of the heat sink, the reflector sections and the drive;

FIG. 12 is an end elevation view, partly broken away,

. illustrating two lamp housings embodying the invention as arranged in side-by-side relation, illustrating the common drive for the shutter sections;

FIG. 13 is a view similar to FIG. 12 but illustrating three lamp housings arranged side-by-side, including the common drive; and

FIG. 14 is a view similar to FIG. 6 but illustrating an alternative embodiment of the heat sink.

DESCRIPTION OF THE I PREFERRED EMBODIMENTS Referring first to FIGS. 1, 2, 3 and 5, a lamp housing embodying the invention is generally indicated at 10 as including two lamp enclosures 16 in face-to-face relation, a conduit forming closure 25 at one side, and a conduit forming enclosure 25' at the opposite side. In the case of a single lamp unit as shown in FIGS. 1 and 2, the conduit closure for the lamp enclosure 16 having a lamp therein comprises a conduit closure 25, having a gear housing 26 at one end, and the other lamp enclosure 16, which does not contain a lamp 20, is closed by a conduit enclosure which does not have a gear housing 26. However, when a unit is to have two lamps 20, such as the lamp housing 10' shown in FIG. 3, the outer side of each lamp enclosure 16 is closed by a lamp enclosure 25 having a gear housing 26 at one end. Each lamp enclosure 16 is formed, at one end, with louvers 17 communicating with the conduit closure 25 or 25', as the case may be, and at the other end with an outlet conduit 18 also communicating with the conduit closure 25 or 25. An exhaust fan or the like is connected to the conduits 18 so that cooling air is drawn into. the lamp housing through the louvers l7, flows through a coolant duct 35, as best seen in FIG. 5,

r and exits through the conduits 18. The formation of the duct 25 will be discussed moe fully hereinafter.

Each lamp enclosure 16 has, interiorly thereof, at each end, an outer baffle or partition 21, an intermediate baffle or partition 22, and an inner baffle or partition 23, all of which are parallel to each other, and which are interconnected by relatively long side walls 19. Also at each end, each lamp enclosure has, adjacent its inner side, inwardly extending baffles 24 so that, when two lamp enclosures are superposed in faceto-face relation, the flanges 24 are in overlying relation with each other. Such superposed lamp enclosures 16 are hingedly interconnected at one end by a hunge 27, and are interconnected at the opposite 'end by a releasable catch 28. In actual construction, the baffles 21, 22 and 23 and the flanges 24 of each lamp enclosure 16 form part of a metal casting to which there is secured a sheet metal skin or outer casing formed with the louvers 17 and with a nipple forming part of the associated conduit 18. The securement of the outer skin to the casting may to effected by suitable screws or studs.

Each lamp enclosure 16 has secured to the entering or web inlet side wall thereof a light shield 30"and to the web outlet side thereof a light shield 30, the light shields 30 and 30' of the two superposed lamp enclosures 16 forming a conjoint light shield which is generally trapezoidal in transverse elevation, and the outer wall of each light shield is formed with a centralized substantially retangular slot 31, the two slots of the superposed light enclosures 16 forming entry and exit slots for the printing web to be dried. A pair of brackets 32 are secured to the lower lamp enclosure 16 both in the case of the single lamp unit shown in FIGS. 1 and 2 and in the case of the two-lamp unit shown in FIG. 3, and brackets 32 are adapted to be pivotally connected to support pillars 33 by pivot pins 34, so that the units can be located from the vertical orientation shown in FIGS. 1 through 4, where they are in operative relation with a printing web 40, to a horizontal orientation for inspection, maintenance, repair or replacement.

Each coolant duct enclosure 25 or 25' is formed of sheet metal and has longitudinally extending sidewalls 36 reinforced by rectangular box-shape elongated reinforcements 37, each reinforcement 37 being secured to the inner surface of the wall 36 to extend the full length thereof and projecting outwardly of the inner edge of the associated wall 36. When a coolant conduit enclosure 25 or 25' is assembled with a lamp enclosure 16, the reinforcements 37 rest on shelves or supports 38 secured to the inner surfaces of the walls 19 of the lamp enclosure, with the walls 36 and 19 being substantially flush with each other. For a purpose to be described, each baffle 21, 22 and 23 is formed with a pair of symmetrically arranged small apertures 41, which are spaced equidistantly from the central longitudinal vertical plane of the associated lamp enclosure. Between the apertures 41 therein, each outer baffle 21 is formed with a central keyhole slot 42 which is aligned with circular holes 42' in each of the baffles 22 and 23. The apertures 41 in the three baffles are longitudinally aligned with each other. The apertures 42 provide for the insertion of lamp sockets 43, having leads 44, into the apertures 42 and the two lamp sockets 43 in each lamp enclosure mount a mercury vapor ultraviolet lamp 20. This mounting is best illustrated in FIGS. 8 and 9.

Referring again to FIGS. 1, 2, 3 and 5, the gear housings 26 serve as enclosures for motors 45 which are unitary with reduction gears 46 which, when a coolant conduit closure 25 or 25 is mounted on a lamp enclosure 16, are disposed in the lamp enclosure outwardly of the outer baffle 21 at one end thereof. An output shaft 47 extends horizontally from each reduction gear 46 and through one set of aligned apertures 41 in the baffles 21, 22 and 23. A drive shaft 58, in axial alignment with each drive shaft 47, extends through the apertures 41 in the baffles 21, 22 and 23 at the opposite end of the lamp enclosure 16. Shafts 47 and 48 have their inner ends secured to reflectors 50 described more fully hereinafter. Shafts 47 and 48 extend through suitable bearings 51 in the apertures 41 in the inner and outer baffles 21 and 23. The other sets of apertures 41 in the baffles 21, 22 and 23 receive idler shafts 52 supported in the same manner as the drive shafts 47 and 48.

Each drive shaft 47 has secured thereto, adjacent reduction gear 46, a chain sprocket 53 for a purpose to be described. inwardly of sprocket 53, a gear 54 is secured to each drive shaft to rotate therewith and meshes with an identical gear 56 on the adjacent idler shaft 52. Similarly, shaft 48 has a gear 54 secured thereon and meshing with a gear 56 on the adjacent idler shaft 52. Thus, upon operation of drive motor 45 and through reduction gear 46, the reflector sections 50 are simultaneously angularly displaced. As best seen in FIGS. 5, 7 and 7a, gears 54, 54 and 56 have eccentrically articulated thereto links 57 whose upper ends are articulated to a heat sink 60 disposed in coolant conduit 35. Thus, when the gears are rotated in the direction of the arrow shown in FIG. 7, heat sink 60 is raised to an upper limiting position and, when the gears are rotated as indicated by the arrows in FIGS. 7a, heat sink 60 is lowered to a lower limiting position. While sprockets 53 have been illustrated as secured to drive shafts 47, they may be secured either to drive shafts 47 or to idler shafts 52, in accordance with the particular arrangement of multiple lamp housings.

Heat sink 60 is preferably an aluminum casting in the form of a flat elongated substantially rectangular plate 61 having a series of ribs 62 extending along its upper surface. At each corner, and as best seen in FIG. 11, plate 61 is formed with a substantially rectangular de pending lug 63, and links 57 are pivotally connected to these lugs. In an upper position, shown in FIGS. 6 and 7, heat sink 60 forms an upper wall for coolant conduit 35 and, in its lower position, as shown particularly in FIGS. 60 and 7a, heat sink 60 rests on the castings forming the baffles 21, 22 and 23 and forms a lower wall of coolant conduit 35, with ribs 52 projecting into coolant conduit 35.

Each'reflector section 50 comprises a transversely elliptically arcuate casting 58, of aluminum or the like, having ribs 64 on its outer surface extending longitudinally thereof. Segmental end walls 66 extend inwardly from the opposite ends of each casting 58, and end walls 66 are formed with central hubs 67 secured to the respective shafts 47, 48 and 52. Along each longer edge, the elliptically arcuate elements 58 are formed with inturned lips 68 so that reflectors 55 may be seated thereinto in conforming relation therewith. Flanges 71 project outwardly from the normally upper edge of each casting 58 and these flanges have ribs 72 extending therealong. In the operative position of the reflector sections 50, as shown in FIG. 6, ribs 72 abut each other to complete the upper enclosure for lamp 20. In the shutterflposition of reflector sections 50, as shown in FIG. 6a, the flanges 71 are coplanar and substantially contiguous to the inner surface of the side 6 walls 19 of the lamp enclosure 16. These side walls 19 may also have box-shaped heat reflecting elements 74 secured thereto.

In a typical arrangement, four lamp housings may be assembled as a unit adjacent the web exit side of each of a pair of printing presses 65 to cure the printed web. Each unit 70 includes a pair of lamp housings l0 and 10, such as shown in FIG. 3, and a pair of lamp housings identical with the lower housing shown in FIG. 10 juxtaposed to the housings 10 and 10, with each of the latter having reflector section driving means. The trailing pair of lamp housings 10 does not have any reflector section driving means, and the reflector sections thereof are driven in a manner which will be described in connection with FIGS. 12 and 13. The upper and lower trailing lamp housings in FIG. 4 are designated, respectively, 108 and 10B, and are identical with the lamp housing sections 108 of FIGS. 1 and 2. With web 40 moving through the lamp housing assembly 70, the lamps 20 are energized and the reflector sections 50 of each lamp housing occupy the position shown in FIG. 6, with the driving gears occupying the position shown in FIG. 7. In this position, the reflector sections 50 conjointly define an elliptical reflector whose first focus is at the lamp 20 and whose second focus is at the plane of travel of web 40. Cooling air is drawn in through the louvers 17 by an exhaust fan or the like connected to the conduits 18, so that the heat of the lamp is absorbed by the reflector sections 50 and is transferred, particularly through the ribs 64, to the coolant conduit 35.

If the travel of the web is interrupted, suitable control means energize the driving motors 45 to rotate the gears 54 and 56 from the position shown in FIG. 7 to the position shown in FIG. 7a. This immediately moves reflector sections 50 to the position shown in FIG. 6a, wherein the reflector sections block light and heat from lamp 20 impinging on the now stationary web 40. At the same time, and through the links 57, heat sink 60 is moved to its lowerposition, as shown in FIG. 6a. The heat from the lamp, as reflected by the reflector sections 50, is absorbed by the heat sink 60 and transferred to the ribs 62 into the coolant conduit 35 whose lower wall is now defined by the heat sink 60. Simultaneous with the movement of reflector 50 and heat sink 60, the power applied to lamp 20 is reduced, preferably by about half, by a switch arrangement not shown. The lamp is not completely extinguished since no coolant air flows over the lamp and is capable of essentially instant full power operation upon the restarting of the web and repositioning of the reflector and heat sink. Nevertheless, web 40 is fully protected from the light and heat of lamp 20, of each lamp housing while the web remains stopped.

When a web which is narrower than normal is used, auxiliary light shields 75 are provided, as shown in FIGS. 5 and 10. These light shields are sheet metal plates which are bent into a U-form with their bights 76 is substantial engagement with opposite longitudinal edges of web 40 and their legs 77 frictionally embracing the flanges 24 of the superposed lamp enclosures 16. The legs 77 may be narrow to provide shoulders 78 serving as abutments for properly locating the light shield 75.

FIGS. 12 and 13 illustrate units having plural lamp housings embodying the invention, including a lamp housing 10A having a driving motor 45 and a reduction gearing 46 and one or more lamp housings C which are identical with the lamp housings 10B of FIGS. 1 and 2 except that gears are provided on the shafts 47, 48 and 52, as well as sprockets 53. In the arrangement of FIG. 12, a multiple unit 80 comprises a lamp housing 10A in side-by-side relation with a lamp housing 10C, the construction of the lamp housings being as described above. ln order to simultaneously operate the reflector sections 50 and movable heat sinks 60 of the two lamp housings in unison, an endless chain 81 is trained around a sprocket 53 secured on shaft 52 of lamphousing 10C.

The unit 80', shown in FIG. 13, differs from the unit 80 only in that two lamp housings 10C are associated with a single lamp housing 10A. in this arrangement, a sprocket 53 is secured to the shaft 52 of lamp housing 10A and a sprocket 53 is secured to the shaft 52 of the outermost lamp housing 10C. The innermost lamp housing 10C, immediately next to lamp housing 10A, has a sprocket 53 secured to its shaft 47. An endless chain 53 is trained around the sprockets 53 in lamp housing 10A and in the outermost lamp housing 10C, as well as having one run trained over an idler sprocket 83 in the intermediate housing 10C. in housing 10C, the upper run of chain 82 engages the sprocket 53 from beneath. in both units 80 and 80', all of the reflector sections 50 and all three heat sinks 60 are operated in the same direction simultaneously. While a two unit assembly is shown in FIG. 12 and a three unit assembly in H6. 13, with only the upper lamp housings being shown for each assembly, it will be appreciated that more than three units may be assembled in side-by-side relation. and that one or more of the lamp housings of each unit may have associated therewith a lower lamp housing in the same manner as shown, for example, in FIG. 3.

FIG. 14 illustrates an alternative embodiment of the heat sink. in this embodiment of the invention, heat sink 85 is stationary or fixed against vertical displacement. and rests on the supports 38. Heat sink 85 includes a flat plate 84 having three ribs 86 extending upwardly from its upper surface and into the coolant duct 35', which is reduced in height by a channel member 87 secured on the inner surface of its upper wall, so that the coolant duct 35' is delimited vertically by the plate 84 and the channel element 87.

In the embodiment of the invention shown in FIG. 14, the fixedly positioned heat sink 85 is water cooled in addition to being air cooled. For this purpose, coolant tubes 90 are positioned between the adjacent ribs 86 and have coolant fluid, such as water, circulated therethrough. Clamps 91 serve to hold coolant tubes 90 in position. in this modification of the invention, the lamp housing can be reduced in height and the mechanism for moving the heat sink is not required. Lamp would still be reduced in power by switching means (not shown) when the reflector sections are in their second or shutter position.

It will be noted that in the different embodiments of the invention, air entering through the louvers 17 can flow not only through the coolant conduits 35 and 35 but also in contact with the reflector sections 50, when the latter are joined to form the elliptical reflector. in the position of the reflector sections shown in FIG. 6, the air flow through the louvers l7 and through the housing and out through the conduit 18 cools reflector sections 50. The air flow is such that it is never in contact with the lamp.

it will thus be seen that the objects set forth above, and those made apparent from the preceding description, are efliciently attained and, some certain changes may be made in the above construction without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

it is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

What is claimed is:

l. A housing for an ultraviolet lamp, comprising, in combination, side and end walls defining a relatively elongated lamp enclosure having an elongated opening at one side thereof; an elongated ultraviolet lamp mounted in said end walls; a pair of elliptical reflector sections mounted in said enclosure for rotation about respective axes extending in spaced parallel relation to said lamp; drive means operable to rotate said reflector sections between a first open reflector position in which they form an elliptical reflector having a first focus at said lamp and a second focus at the plane of said opening, and a second closed shutter position in which they are interposed between said lamp and said opening, and vice versa; and lamp enclosure cooling means at the opposite side of said lamp enclosure.

2. A housing for an ultraviolet lamp, as claimed in claim 1, in which said lamp enclosure cooling means includes a coolant duct extending longitudinally of said lamp enclosure at said opposite side of said lamp enclosure; and coolant inlet and outlet means at respective opposite ends of said coolant duct for flow of a gaseous coolant through said coolant duct.

3. A housing for an ultraviolet lamp, as claimed in claim 2, in which said lamp enclosure cooling means further includes a heat sink extending longitudinally of said coolant duct and in heat transfer relation with said lamp and said reflector sections.

4. A housing for an ultraviolet lamp, as claimed in claim 3, in which said heat sink comprises a substantially flat plate having a substantially planar inner surface facing said lamp and said reflector sections, and a series of ribs extending longitudinally of the outer surface of said plate.

5. A housing for an ultraviolet lamp, as claimed in claim 4, in which said coolant duct has an outer wall extending substantially parallel to said opposite side of said lamp enclosure; said heat sink being movable between a first position in which it is disposed in said coolant duct intermediate the outer wall of said coolant duct and said opposite side of said lamp enclosure, and a second position in which it is at the said opposite side of said lamp enclosure and forms an inner closure wall for said coolant duct, extending parallel to said outer wall; and means connecting said heat sink between its first and second positions and vice versa.

6. A housing for an ultraviolet lamp, as claimed in claim 5, including a drive shaft secured to and rotatably supporting one of said reflector sections; an idler shaft secured to and rotatably supporting the other of said reflector sections; said driving means being operatively connected to said drive shaft; respective gears on said drive and idler shaft interrneshing with each other whereby said reflector sections are conjointly moved between their first closed reflector position and their second closed shutter position, and vice versa; and respective links each having one end articulated eccentrically to a respective one of said gears and the opposite end articulated to said heatsink for moving saidheat sink to the first heat sink position responsive to movement of said reflector sections to the first closed reflector position and for moving said heat sink to the second heat sink position responsive to movement of said reflector sections to said second closed shutter position; said links constituting the means connecting said heat sink to said driving means.

7. A housing for an ultraviolet lamp, as claimed in claim 4, in which said coolant duct has an outer wall extending longitudinally parallel to said opposite side of said lamp enclosure; said heat sink being fixedly positioned substantially at said opposite side of said lamp enclosure and constituting an inner wall of said coolant duct; and liquid coolant ducts extending longitudinally of said outer surface of said flat plate for flow of liquid coolant therethrough to absorb, from said heat sink, heat transferred to said heat sink from said reflector sections and saidlamp.

8. A housing for an ultraviolet lamp, as claimed in claim 2, including side and end walls defining a relatively elongated second lamp enclosure having an elongated opening atone side thereof; said second lamp enclosure being arranged in facing relation with said firstmentioned lamp enclosure with said elongated openings congruent with each other; and a second coolant duct extending longitudinally of the opposite side of said second lamp enclosure and having coolant inlet means at one end thereof and coolant outlet means at the other end thereof for cirulation of a gaseous coolant therethrough.

9. A housing for an ultraviolet lamp, as claimed in claim 8, including a respective pair of light shields secured to each lamp enclosure, each extending along a respective side wall of the associated lamp enclosure; each light shield being completely closed except for an open and coplanar with the elongated opening at one side of the associated lamp enclosure; corresponding light shields of the two lamp enclosures abutting each other in congruent relation; each light shield having an outer end wall extending substantially parallel to the side wall of the associated lamp enclosure and formed with a rectangular notch therein; said notches of correspondingly located light shields conjointly defining entry and exit slots for passage of a printed web through said lamp housing.

10. A housing for an ultraviolet lamp, as claimed in claim 8, including a second elongated ultraviolet lamp mounted in the end walls of said second lamp enclosure; a pair of second elliptical reflector sections mounted in said second enclosure for rotation about respective axes extending in spaced parallel relation to said second lamp; and second driving means operable to rotate said second reflector sections between a first closed reflector position in which they form an elliptical reflector having a first focus at said second lamp and a second focus at the plane of said elongated opening in said second lamp enclosure and a second closed shutter possition in which they are interposed between said second lamp and said last-named opening, and vice versa.

11. A housing for an ultraviolet lamp, as claimed in claim 1, including pairs of auxiliary light shields disengageably and interchangeably mounted in said lamp enclosure in substantially the plane of said elongated opening at one side thereof, and reducing the lateral width of said elongated opening to correspond to the lateral width of a relatively narrow printed web moved across said elongated opening when said housing is in said operative position.

12. A housing for an ultraviolet lamp, as claimed in claim 11, in which each auxiliary light shield comprises a flat plate bent back on itself to form a bight and a pair of legs extending from said bight; the bights of each pair of auxiliary light shields defining the path of movement of a printed web; the legs of each auxiliary shield being frictionally embraceable with a respective inwardly extending flange at said elongated opening at one side of said lamp enclosure.

13. In combination, at least two housing for an ultraviolet lamp, as claimed in claim 1, arranged in juxtaposed relation; each housing having a respective pair of shafts secured to and rotatably supporting the reflector sections therein; respective gear means in each housing interconnecting the shafts of the respective pair therein for conjoint rotation in opposite directions; respective sprockets each secured to one shaft in each housing; said driving means being included in only one of said housings; and chains interconnecting the sprockets of all said housings, whereby all of said reflector sections are conjointly rotated between their two said positions by the single driving means in said one housing.

14. The combination as claimed in claim 13, in which each lamp cooling means includes a respective coolant duct extending longitudinally of the associated lamp enclosure and having a coolant inlet at one end and a coolant outlet at the opposite end for flow of coolant therethrough; and a respective heat sink in each lamp housing operatively associated with the respective coolant duct, the respective lamp and the respective reflector sections thereof.

15. A housing for an ultraviolet lamp, for use in drying printed webs of a web printing press, as recited in claim 1, wherein said opening extends transversely across the path of movement of said printed web. 

1. A housing for an ultraviolet lamp, comprising, in combination, side and end walls defining a relatively elongated lamp enclosure having an elongated opening at one side thereof; an elongated ultraviolet lamp mounted in said end walls; a pair of elliptical reflector sections mounted in said enclosure for rotation about respective axes extending in spaced parallel relation to said lamp; drive means operable to rotate said reflector sections between a first open reflector position in which they form an elliptical reflector having a first focus at said lamp and a second focus at the plane of said opening, and a second closed shutter position in which they are interposed between said lamp and said opening, and vice versa; and lamp enclosure cooling means at the opposite side of said lamp enclosure.
 2. A housing for an ultraviolet lamp, as claimed in claim 1, in which said lamp enclosure cooling means includes a coolant duct extending longitudinally of said lamp enclosure at said opposite side oF said lamp enclosure; and coolant inlet and outlet means at respective opposite ends of said coolant duct for flow of a gaseous coolant through said coolant duct.
 3. A housing for an ultraviolet lamp, as claimed in claim 2, in which said lamp enclosure cooling means further includes a heat sink extending longitudinally of said coolant duct and in heat transfer relation with said lamp and said reflector sections.
 4. A housing for an ultraviolet lamp, as claimed in claim 3, in which said heat sink comprises a substantially flat plate having a substantially planar inner surface facing said lamp and said reflector sections, and a series of ribs extending longitudinally of the outer surface of said plate.
 5. A housing for an ultraviolet lamp, as claimed in claim 4, in which said coolant duct has an outer wall extending substantially parallel to said opposite side of said lamp enclosure; said heat sink being movable between a first position in which it is disposed in said coolant duct intermediate the outer wall of said coolant duct and said opposite side of said lamp enclosure, and a second position in which it is at the said opposite side of said lamp enclosure and forms an inner closure wall for said coolant duct, extending parallel to said outer wall; and means connecting said heat sink between its first and second positions and vice versa.
 6. A housing for an ultraviolet lamp, as claimed in claim 5, including a drive shaft secured to and rotatably supporting one of said reflector sections; an idler shaft secured to and rotatably supporting the other of said reflector sections; said driving means being operatively connected to said drive shaft; respective gears on said drive and idler shaft intermeshing with each other whereby said reflector sections are conjointly moved between their first closed reflector position and their second closed shutter position, and vice versa; and respective links each having one end articulated eccentrically to a respective one of said gears and the opposite end articulated to said heat sink for moving said heat sink to the first heat sink position responsive to movement of said reflector sections to the first closed reflector position and for moving said heat sink to the second heat sink position responsive to movement of said reflector sections to said second closed shutter position; said links constituting the means connecting said heat sink to said driving means.
 7. A housing for an ultraviolet lamp, as claimed in claim 4, in which said coolant duct has an outer wall extending longitudinally parallel to said opposite side of said lamp enclosure; said heat sink being fixedly positioned substantially at said opposite side of said lamp enclosure and constituting an inner wall of said coolant duct; and liquid coolant ducts extending longitudinally of said outer surface of said flat plate for flow of liquid coolant therethrough to absorb, from said heat sink, heat transferred to said heat sink from said reflector sections and said lamp.
 8. A housing for an ultraviolet lamp, as claimed in claim 2, including side and end walls defining a relatively elongated second lamp enclosure having an elongated opening at one side thereof; said second lamp enclosure being arranged in facing relation with said first-mentioned lamp enclosure with said elongated openings congruent with each other; and a second coolant duct extending longitudinally of the opposite side of said second lamp enclosure and having coolant inlet means at one end thereof and coolant outlet means at the other end thereof for cirulation of a gaseous coolant therethrough.
 9. A housing for an ultraviolet lamp, as claimed in claim 8, including a respective pair of light shields secured to each lamp enclosure, each extending along a respective side wall of the associated lamp enclosure; each light shield being completely closed except for an open and coplanar with the elongated opening at one side of the associated lamp enclosure; corresponding light shields of the two lamP enclosures abutting each other in congruent relation; each light shield having an outer end wall extending substantially parallel to the side wall of the associated lamp enclosure and formed with a rectangular notch therein; said notches of correspondingly located light shields conjointly defining entry and exit slots for passage of a printed web through said lamp housing.
 10. A housing for an ultraviolet lamp, as claimed in claim 8, including a second elongated ultraviolet lamp mounted in the end walls of said second lamp enclosure; a pair of second elliptical reflector sections mounted in said second enclosure for rotation about respective axes extending in spaced parallel relation to said second lamp; and second driving means operable to rotate said second reflector sections between a first closed reflector position in which they form an elliptical reflector having a first focus at said second lamp and a second focus at the plane of said elongated opening in said second lamp enclosure and a second closed shutter possition in which they are interposed between said second lamp and said last-named opening, and vice versa.
 11. A housing for an ultraviolet lamp, as claimed in claim 1, including pairs of auxiliary light shields disengageably and interchangeably mounted in said lamp enclosure in substantially the plane of said elongated opening at one side thereof, and reducing the lateral width of said elongated opening to correspond to the lateral width of a relatively narrow printed web moved across said elongated opening when said housing is in said operative position.
 12. A housing for an ultraviolet lamp, as claimed in claim 11, in which each auxiliary light shield comprises a flat plate bent back on itself to form a bight and a pair of legs extending from said bight; the bights of each pair of auxiliary light shields defining the path of movement of a printed web; the legs of each auxiliary shield being frictionally embraceable with a respective inwardly extending flange at said elongated opening at one side of said lamp enclosure.
 13. In combination, at least two housing for an ultraviolet lamp, as claimed in claim 1, arranged in juxtaposed relation; each housing having a respective pair of shafts secured to and rotatably supporting the reflector sections therein; respective gear means in each housing interconnecting the shafts of the respective pair therein for conjoint rotation in opposite directions; respective sprockets each secured to one shaft in each housing; said driving means being included in only one of said housings; and chains interconnecting the sprockets of all said housings, whereby all of said reflector sections are conjointly rotated between their two said positions by the single driving means in said one housing.
 14. The combination as claimed in claim 13, in which each lamp cooling means includes a respective coolant duct extending longitudinally of the associated lamp enclosure and having a coolant inlet at one end and a coolant outlet at the opposite end for flow of coolant therethrough; and a respective heat sink in each lamp housing operatively associated with the respective coolant duct, the respective lamp and the respective reflector sections thereof.
 15. A housing for an ultraviolet lamp, for use in drying printed webs of a web printing press, as recited in claim 1, wherein said opening extends transversely across the path of movement of said printed web. 